When I was in elementary school we used to practice two emergency drills: one for fire which was an evacuation, and another for a nuclear bomb, commonly known as a duck and cover. During the Cold War, the Red Scare, a Soviet Union attack, was on everyone’s mind.

Then the 1971 Sylmar earthquake happened and all the schools began practicing earthquake drills.

After the shootings at Columbine in 1999, soon lockdown drills were added to the emergency drill repertoire.

I have experienced two real lockdowns. Thank God, neither one turned out badly. But I can tell you that remaining quiet and motionless on the floor, uncomfortably cramped under a table for two hours is terrifying, trying to peek through vertical blinds for any shadow approaching.

And now the history books will add Sandy Hook in 2012. I’m not sure if this stomach-wrenching tragedy will generate any changes in emergency procedures. However, here’s hoping smart people will reexamine the lockdown procedure.

I’ve never understood the logic behind the lockdown drill. Most school shootings are perpetrated by students who attend those campuses, meaning, they are fully aware of the lockdown drill: teachers lock the doors, turn off the lights, and everyone hides in a corner. No one is fooled that that classroom is actually empty. Of course, a locked door makes it a little harder versus an unlocked one. However, any killer can easily shoot out a door and find a classroom of sitting duck victims.

From what little is known about last Friday’s horror, the murderer calmly walked into rooms and executed kids who were motionless.

I understand the logic of not having kids run wild. A maniac is likely to shoot a moving target. However, at least there is a chance of escape. Crouching under a table only works on the completely random chance that the shooter doesn’t choose that classroom.

The only good that can come out of Sandy Hook is for security measures at schools be reevaluated, and for politicians to rethink laws on assault weapons.

While we all know these tragic events are thankfully quite rare, they unsettle all of us: parents, teachers, children.

It wasn’t that long ago when society feared a foreign intruder harming our nation. Now, that intruder is among us.

BRIAN CROSBY is a teacher in the Glendale Unified School District and the author of "Smart Kids, Bad Schools and The $100,000 Teacher." He can be reached at brian-crosby.com.